GATE XL Life Sciences 2010 Previous Year Question Paper Zoology

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GATELifeSciences(XL)2010(GraduateAptitudeTestinEngineering:OriginalQuestionPaper)

Zoology‐OptionalQuestionPaper

Questions1–10carries1markeach:

1. From the perspective of developmental origin. Which of the following structures ishomologoustoatortoiseshell?

a. Exoskeletonofalobsterb. Bonesofafishc. Skullofhumansd. Feathersofbirds

2. Acoelomatesarecharacterizedby:a. Theabsenceofcavitysurroundingtheinternalorgansb. Thepresenceofhugebodycavity,asincaseofterrestrialanimalsc. Thepresenceofairsacs,asincaseofbirdsd. Theabsenceofbraininagroupofextinctspecies.

3. Identify the phylum that is characterized by the animals that have segmentedappendages.

a. Cnideriab. Poriferac. Arthropodad. Mollusca

4. Whichoneof the following is thesmallestbiologicalunit capableofevolvingovertime?

a. Acellb. Anindividualorganismc. Apopulationd. Aspecies

5. In case of parasites that requiremultiple hosts to complete their life cycle, whatdoesdefinitivehostmean?

a. Itisthehostthatharborsthesexualstagesoftheparasiteb. Itisthehostinwhichtheparasitereproducessexuallyc. Itisthehostinwhichtheparasitefeedsd. Itisthehostinwhichtheparasiteremainindormantstage

6. Enzymescatalyzebiochemicalreactionsby:a. Sequesteringtheproducts(s)b. Decreasingthe∆Gofthereactionwww.ea

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c. Increasingthe∆Gofthereactiond. Stabilizingthetransitionstateofthereaction.

7. WhichoneofthefollowingresultfromMendel’smonohybridcrossisthestrongestevidenceagainsttheblendingtheory?

a. 3:1ratioofphenotypesintheF1generationb. AllprogenyoftheF1generationexhibitedthedominantphenotypec. TherecessivephenotypeshowedupintheF2progenyd. Theobservationofincompletedominance

8. Inthecontestofcelldifferentiation,lateralinhibitionisreferredtoasthe:a. Formationoftwodistinctcelltypeswithinauniformfieldb. Inhibitionofformationofadistinctcelltypenexttoanexistingcelltypec. Inhibitionofstemcellstowardsself‐renewald. Inhibitionoferythopoesisinthelateralplatmesoderm

9. Ascomparedtopeptidehormones,steroidhormonestakemoretimetoactivateacellularresponse,because

a. Steroidhormonesshownonspecificbindingwithdiversesetsofreceptorsb. Steroidhormonesactsthroughareceptorwhichisatranscriptionfactorc. Cellsthatrespondtosteroidhormonesaredormantinnatured. Peptide hormones are not transported through plasma while steroid

hormonesare.10. Inallopatricmodeofspeciation,anewspeciesformsdueto:

a. Geographicisolationb. Geneticdriftc. Formationofafewfertileindividualsthatcannotmatewithothermembers

ofthesamespecieslivinginthesamegeographicalaread. Theformationofallopolyploidcondition

Questions11–20carries2markseach:

11. Neurogen (Ngn) a newly discovered protein in chicken is produced by thenotochord and the floor plate (FP). Ngn induces cells of the neural tube (NT) tobecomeneurons.Itisknownthatfromventraltodorsaldirectioncellsatdifferentlevels give rise to distinct types of neuronal cells. Which of the followingobservationswillcastadoubtintheclaimthatNgnisamorphogen?

a. Ngnisacytosolicproteinb. Artificial mis‐expression of Ngn at identical level throughout NT does not

affecttheneuronalcelltypesformedintheNTc. Ngnisanintegralmembraneproteind. Alloftheabovewww.ea

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12. Analienspecieshasbeendiscoveredwithverysimilargeneticmakeupasthatoftheexistingspeciesonplanetearthwithcertaindifferences.Thegeneticmaterialofthisnewspecies isreferredtoasDNA*.Thebuildingblocksof thegeneticmaterials isknown as Nucleotide*. The proteins of the new species (Protein*) is made up ofAminoAcids*.It has also been discovered that the new species has 5 distinct Nucleotide* asopposedtothefourspeciesonplanetearth.Thenewspecieshas40differentaminoacids*asopposedtothe20forspeciesonplanetearth.Whatshouldbethecodonlength for this new species (the same for species of plant earth is 3)? It may beassumed that the average codondegeneracy of thenew species is very similar tothatofspeciesofplanetearth.

a. 2b. 3c. 4d. 5

13. Whichoneofthefollowingoptionsisnotaviablestrategyfordevelopingafemalecontraceptive?Theadministrationof:

a. Acombinationofsyntheticprogesteroneandestrogenb. Syntheticprogesteronealonec. Ormeloxifene–aselectiveestrogenreceptormodulatord. Asyntheticoxytocin

14. In the field of community ecology, the term “competitive exclusion” refers to twospeciesthatcannotco‐exist:

a. Inacommunityifthenichesareidenticalb. Intwodifferentcommunitiesifthenichesareidenticalc. Iftheecosystemisimbalancedd. Intheeventofavolcaniceruption

15. Duringimmuneresponse,helperT‐cellmemoryagainsttheantigenappearsearlierthantheBmemorycells.Whichoneofthefollowingistheprimaryreasonforthisphenomenon?

a. AffinityofantibodymoleculesproducedbyBcellsisweakerthanthoseofTcells

b. BmemorycellsproliferateatarateslowerthanthatofTcellsc. BcellactivationrequireshelperTcellsd. Thymic selection more rapidly enhances the T cell population than B cell

population16. Oceanshaveenormousimpactonthebiosphere.Identifywhichoneofthefollowing

factorsisNOTinfluencedbythemarinebiome?www.easy

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a. CO2levelintheatmosphereb. Climaticchangeintheterrestrialbiomec. pHofthefreshwaterbodiesd. oxygenlevelinthebiosphere

17. Certain lung fishesthat live insmallstagnant freshwaterpoolsproduceureaasanitrogenouswaste.Whatistheadvantageofthisadaptation?

a. Ureaformprecipitatesanddoesnotaccumulateinthesurroundingwaterb. Lungfishdonotfindenoughwaterforproductionofammoniaandhencethe

nitrogenouswasteisexcretedasureac. Theexcretedureamakesthepooluninhabitabletothepredatorsofthelung

fishd. Urearequiresmuchlessenergyforitssynthesisthanammonia

18. Hamilton’srulemeasurestheprobabilityofwhetherornotnaturalselectionwouldfavour an altruistic act. Which one of the following statement best explainsHamilton’srule.

a. Thereceiverandnotthealtruistisbenefitedb. ThereceiverisanoffspringandNOTssiblingofthealtruistc. Thebenefittothereceiver,reducedbythecoefficientofrelatedness,exceeds

thecosttothealtruistactd. Thealtruistsurvivesinanaltruistacttosavehis/herrelatedindividuals

19. In a cross between plants with purple andwhite coloured flowers, the followingresults were obtained in the F1 generation (assume that both varieties are truebreeding): 100 plants with white flowers; 150 straw yellow; 200 yellow; 245greenish yellow; 500 green; 440 light blue; 400blue; 300 indigo; 253purple and100darkpurple.Thesedatasupportwhichoneofthefollowingconclusion?

a. FlowercolourinthisspeciesdoesnotfollowMendelianinheritanceb. Lawofincompletedominancec. Coloursareco‐dominantinthisspeciesd. Flowercolourinthisspeciesisdeterminedbymultiplegenes

20. Whichoneofthefollowingismostcrucialforthesuccessofvaccination?a. AntigenpresentationbyThelpercellsb. Complementsystemc. Presenceoflong‐livedantigenspecificlymphocytesd. SelectionofBcellsinthelymphoidtissue

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GATE XL Life Sciences 2010 Previous Year Question Paper Zoology